Patent GB-846447-A (GB)
Title: Improvements relating to explosively actuated driving tools
IPC: B25C1/14
Filed: 1958-03-19
Abstract: 846,447. Explosive actuated tools for driving nails. MINE SAFETY APPLIANCES CO. March 19, 1958 [April 9, 1957], No. 8773/58. Class 119. An explosive-actuated driving tool has a chambered barrel 50 sliding in a carriertube 3 from which its front end projects. A sleeve 80 slides on the tube and the barrel but is fixed to the latter for rotation, so that in the firing position, when the barrel is locked to a breech block 6 at the rear of the tube, it cannot be rotated to unlock until the sleeve is released to rotate on the tube. The sleeve and barrel can then be moved forward together from the breech block to provide an opening 51 for reloading. Movement of the sleeve 80 on the barrel 50 is restricted longitudinally and inhibited rotationally by a capscrew 81 in a groove 82, but the two can be connected by a spring-catch 87 - 88 to slide together on the tube 3. Forward movement of the barrel is restricted by a lug 49 on its rear abutting against the lip of the opening 51 and it can be retained there in a notch whilst the sleeve is pulled back over it. Primarily the tool is for driving nails 66 that are located in a shoulder 65 in a chuck 60 that for loading can be pulled forwards in the barrel to align one of its slots 64 with a slot 67 which is exposed by pulling the sleeve 80 to the rear. The nail is driven indirectly by a plunger and piston 68 - 69 whose energy can be varied by turning a nut 77 on the barrel to move a longitudinal bar (Fig. 7, not shown), that alters the initial position of the piston 69 in the chamber 70. After loading, the barrel and sleeve are pushed back and rotated until the barrel lug 49 is fully engaged in a "bayonet" type joint formed by a groove 48 in a front cavity 47 of the breech block 64 the sleeve 80 is then pushed further back until a recess in its rearward face 85 engages a pin 83 on the tube 3 to prevent unlocking of the barrel until the sleeve has been pulled forward again. Firing and safety mechanism. A firing pin 13 is formed on a cup 14 fixed to slide on a rod 15 which is screwed into a slider 17 in a bore 18 of the stock-body 2 joined to the tube 3 by screws 4. The pin 13 is urged forward by a firing-spring 22 compressed between a collar 21 and trip-ring 23 both sliding on the rod. A spring 24 is compressed between the slider 17 and a shoulder 36 on sprung segments 37 and 38 of a firing-spring compressor 37 - 38 - 39 - 41 to retract the firing pin from the firing-hole 11. When a gripper 32 on the stock is squeezed, a linkage 31 - 26 - 25 forces the slider 17 forward but the flange 43 on the collar 21 is held back by ridges 42 inside the segments 37 and 38, so that the firing spring 22 is compressed. A further slight forward movement of the stock relative to the barrel is then capable of causing the front cylinder of the trip-ring 23 to contact the rear cylinder of the collar 21 and force the flange 43 past the ridges 42 to release the cocked striker for firing. A cartridge extractor 54 is provided. Specifications 846,445 and 846,446 are divided from this Specification and describe the same driving tool.